注：该demo建立得比较简单，数据库操作就是查询某张表的数据，然后将查询出来的数据以JSON格式显示在浏览器上
1）流程简介
该demo一共包含4个文件：index.js server.js router.js function.js
其中index.js中连接了数据库，连接成功后，调用server启动函数。
server.js 创建http服务器，并指定端口。
router.js 路由器，根据url地址，调用不同的函数
function.js 各个函数的具体实现（此demo中只有一个）
2) 代码实现
index.js
//加载相应的模块，这儿使用的是postgresql数据库，因此加载的模块是pg。使用不同的数据库可以加载相应
的模块
var pg = require('pg');
//加载内部模块
var server = require("./server");
var router = require("./router");
var func = require("./function");
//将url路径对应到相应的函数
var handle = {};
handle["/"] = func.select;
handle["/select"] = func.select;
//构造连接数据库的连接字符串："tcp://用户名:密码@ip/相应的数据库名"
var conString = "tcp://postgres:postgres@localhost/my";
var client = new pg.Client(conString); //构造一个数据库对象
//连接数据库，连接成功，执行回调函数
client.connect(function(error, results) {
if(error){
console.log('ClientConnectionReady Error: ' + error.message);
client.end();
return;
}
console.log("client.connect OK.\n");
server.start(client,router.route,handle); //启动server
});
server.js
//加载对应的模块
var http = require("http");
var url = require("url");
function start(client,route,handle)
{
//创建http服务器
http.createServer(function(request,response){
var pathname = url.parse(request.url).pathname;
console.log("Request for " + pathname + " received.");
route(client,handle,pathname,response);
}).listen(8888); //指定端口
console.log("Server has started.");
}
exports.start = start;
router.js
function route(client,handle,pathname,response){
console.log("About to route a request for " + pathname);
if(typeof handle[pathname] === 'function'){
handle[pathname](client,response); //执行对应的函数
}else{
console.log("No request handle found for " + pathname +'\n');
response.writeHead(404,{"Content-Type":"text/plain"});
response.write("404 Not found");
response.end();
}
}
exports.route = route;function.js
function select(client,response)
{
console.log("Request handler 'select' was called.");
//执行相应的sql语句
client.query("select * from teacher;",function(error,results){
console.log("in callback function.\n");
if (error)
{
console.log("error");
console.log('GetData Error: ' + error.message);
client.end();
return;
}
if(results.rowCount > 0)
{
//callback(results);
//指定为json格式输出
response.writeHead(200,{"Content-Type":"application/json"});
//先将results 字符串内容转化成json格式，然后响应到浏览器上
response.write(JSON.stringify(results)); response.end(); } });}
exports.select = select;3) 执行结果
(1) http://localhost:8888/select
1) 后台显示：
client.connect OK.
Server has started.
Request for /select received.
About to route a request for /select
Request handler 'select' was called.
in callback function.
2) 浏览器显示:
{
"command":"SELECT",
"rowCount":2,
"oid":null,
"rows":
[
{
"id":"1",
"name":"aaa",
"pwd":"111"
},
{
"id":"2",
"name":"bbb",
"pwd":"222"
}
]
}
(2) http://localhost:8888/
1) 后台显示：
client.connect OK.
Server has started.
Request for / received.
About to route a request for /
Request handler 'select' was called.
in callback function.
2) 浏览器显示:同上 //由于在index.js文件中指定两种情况都访问同一个函数